Refining estimates of the stable carbon isotope signature attributed to methane emissions from boreal wetlands
department or school: Science, Irving K. Barber Faculty of (Okanagan)
department or school: Earth, Environmental and Geographic Sciences, Department of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Hosseini Alhashemi, Azamalsadat
issued: 2020-07-16T21:00:32Z
issued: 2020
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Northern wetlands are a major global source of methane (CH₄) emissions to the atmosphere. How carbon cycling in these peat-rich ecosystems will respond to ongoing climate change remains uncertain. Stable isotopes provide a means to trace CH₄ from different emission sources, including different wetland types; however, upscaling of emissions relies upon accurate knowledge of CH₄ source strengths and isotope composition, and delineation of wetland types and areas. This study developed a comprehensive probabilistic inventory of wetland occurrence in Manitoba, Canada using Earth observation satellite data and ancillary data characterizing vegetation structure and environmental conditions. Google Earth Engine was used to acquire and process synthetic aperture radar (SAR) and multi-spectral data from Sentinel-1 and Sentinel-2 for 2018. Satellite imagery was combined with vegetation structure information, pH and topographic derivatives in a random forest model to predict the occurrence and type of wetland. The approach yielded a high overall predictive accuracy (0.86) and strong discrimination between different wetland types. The results demonstrated a significant role for use of optical variables to model wetland distribution at regional scales when coupled with LiDAR-derived metrics and soil pH data. A literature review identified limited new stable isotope data for wetlands globally but the available data agreed well with previous assessments of δ¹³C(CH₄) values for bogs (-74.9 ± 9.8‰) and fens (-64.8 ± 4.0‰). The δ¹³C(CH₄) values were upscaled using published CH₄ flux rates and the areas of bogs and fens in Manitoba determined in this study. Manitoban bogs and fens are estimated to emit 0.8 ± 0.1 Mt CH₄ yr-¹ collectively, which is a large proportion of total flux from northern Canadian wetlands (4.1 - 6.9 Mt). Integrated δ¹³C(CH₄) values are more negative than compositions typically attributed to wetlands (-62 to -58‰) in global budgets because of the endmember composit…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/75188
note: REFINING ESTIMATES OF THE STABLE CARBON ISOTOPE SIGNATURE ATTRIBUTED TO METHANE EMISSIONS FROM BOREAL WETLANDS by Azamalsadat Hosseini Alhashemi B.Sc. Environmental Engineering, Islamic Azad University, North Tehran Branch, 2002 M.Sc., Environmental Science, Islamic Azad University, Tehran Science and Research Branch, 2005 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE In THE COLLEGE OF GRADUATE STUDIES (Earth and Environmental Sciences) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) June 2020 © Azamalsadat Hosseini Alhashemi, 2020 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Refining estimates of the stable carbon isotope signature attributed to methane emissions from boreal wetlands submitted by Azamalsadat Hosseini Alhashemi in partial fulfillment of the requirements for the degree of Master of Science. Examining Committee: Edward Hornibrook, Department of Earth, Environmental and Geographic Sciences Supervisor Mathieu Bourbonnais, Department of Earth, Environmental and Geographic Sciences Co-Supervisor Jason Pither, Departments of Biology and Earth & Environmental Science Supervisory Committee Member Melanie Jones, Department of Biology University Examiner iii Abstract Northern wetlands are a major global source of methane (CH4) emissions to the atmosphere. How carbon cycling in these peat-rich ecosystems will respond to ongoing climate change remains uncertain. Stable isotopes provide a means to trace CH4 from different emission sources, including different wetland types; however, upscaling of emissions relies upon accurate knowledge of CH4 source strengths and isotope composition, and delineation of wetland types and areas. This study developed a comprehensive probabilistic inventory of wetland occurrence in Manitoba, Canada using Earth observation satellite data and ancillary data character…
has type: Thesis/Dissertation
date issued: 2020-09
is shown at: 10.14288/1.0392428
language: eng
degree discipline: Earth and Environmental Sciences
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/75188